Universal dynamic navigation, surveillance, emergency location, and collision avoidance system and method

• US 5,153,836 A
• Filed: 08/22/1990
• Issued: 10/06/1992
• Est. Priority Date: 08/22/1990
• Status: Expired due to Term

• Current Assignee: Edward J. Fraughton
• Original Assignee: Edward J. Fraughton
• Inventors: Berger, Philip H., Fraughton, Edward J.
• Primary Examiner(s): Chin, Gary
• Application Number:
  US07/571,514
• Time in Patent Office: 776 Days
• Field of Search: 364/452, 364/459, 364/460, 364/461, 340/961, 342/29-32, 342/41, 342/450, 342/451, 342/455, 342/463
• US Class Current: 701/301
• CPC Class Codes: G01S 5/0009 Transmission of position information to remote stations involving assistance data G01S5/0236
• CPC Class Codes: G08G 9/02 Anti-collision systems

Abstract

A craft tracking and collision avoidance system is disclosed. The system allows the positions of a plurality of craft, either on land, sea, or air, or space, to be monitored. Each craft determines its own position using an existing position determining system such as LORAN or GPS. Each craft then transmits a radio frequency signal into which position information, preferably identifying information, and other messages, have been encoded. Each craft broadcasts its position, identifying information and other messages on a regular basis without the need for any interrogation signal. The broadcast position and identification information can be received by other craft and, since each craft has determined its own position, can be used to determine the proximity and identity of other craft, and if the craft are on a collision course. Preferably, the position of all the craft within a predetermined range of a craft is represented on a display in order to give the craft operator a visual indication of traffic surrounding his craft.

Claims

1. A method for announcing the position of a first aircraft at a first position, the first position being within airspace containing a plurality of other aircraft, to a receiver located at a second position not farther than a predetermined range from the first position, the method comprising the steps of:

(a) determining on board the first aircraft the position of the first aircraft relative to a fixed reference;

(b) encoding an identification code, the presence or absence of any current operating communication radio frequency and the position of the first aircraft so that the identification code, the presence or absence of current operating communication radio frequency and the position of the first aircraft can be carried by a first radio frequency signal;

(c) avoiding conflicts with any radio frequency signals present in the airspace which conflict with the first radio frequency signal;

(d) transmitting from the first aircraft the first radio frequency signal carrying the identification code, the presence or absence of any current operating communication radio frequency and the position of the first aircraft;

(e) receiving the first radio frequency signal transmitted from the first aircraft at the second position;

(f) decoding the identification code, the current operating communication radio frequency if any, and the position of the first aircraft from the first radio frequency signal; and

(g) monitoring on a visual display the identification code, the current operating communication radio frequency if any, and the position of the first aircraft within the airspace at the second position so that the position of the first aircraft within the airspace is known relative to the fixed reference, and so that communication can potentially be undertaken with the specifically identified aircraft.

2. A method for announcing the position of a first aircraft at a first position to a receiver located at a second position as defined in claim 1 wherein the step of determining the position of the first craft comprises the step of receiving a LORAN signal.

3. A method for announcing the position of a first aircraft at a first position to a receiver located at a second position as defined in claim 1 wherein the step of determining the position of the first craft comprises the step of receiving a GPS signal.

4. A method for announcing the position of a first aircraft at a first position to a receiver located at a second position as defined in claim 1 wherein the fixed reference exists both within the airspace and outside the airspace.

5. A method for announcing the position of a first aircraft at a first position to a receiver located at a second position as defined in claim 4 wherein the step of determining the position of the first aircraft comprises the step of determining the position of the first aircraft in reference to the fixed reference.

6. A method for announcing the position of a first aircraft at a first position to a receiver located at a second position as defined in claim 5 wherein the step of determining the position of the first aircraft further comprises the step of determining the altitude of the first aircraft.

7. A method for announcing the position of a first aircraft at a first position to a receiver located at a second position as defined in claim 1 or 5 wherein the step of encoding the position of the first aircraft comprises the step of encoding the position of the aircraft into a digital pulse train.

8. A method for announcing the position of a first aircraft at a first position to a receiver located at a second position as defined in claim 7 wherein the step of encoding the position of the first aircraft further comprises the step of translating the position of the first aircraft into an audio signal.

9. A method for announcing the position of a first aircraft at a first position to a receiver located at a second position as defined in claim 1 wherein the step of avoiding conflicts with any conflicting radio frequency signals in the airspace comprises the step of listening for any conflicting radio frequency signals.

10. A method for announcing the position of a first aircraft at a first position to a receiver located at a second position as defined in claim 9 wherein the step of avoiding conflicts with any conflicting radio frequency signals in the airspace comprises the step of waiting a period of time prior to transmission.

11. A method for announcing the position of a first aircraft at a first position to a receiver located at a second position as defined in claim 10 wherein the step of avoiding conflicts with any conflicting radio frequency signals in the airspace comprises the step of waiting a predetermined period of time prior to transmission.

12. A method for announcing the position of a first aircraft at a first position to a receiver located at a second position as defined in claim 10 wherein the step of avoiding conflicts with any conflicting radio frequency signals in the airspace comprises the step of waiting a random period of time prior to transmission.

13. A method for announcing the position of a first aircraft at a first position to a receiver located at a second position as defined in claim 1 or 10 wherein the step of avoiding conflicts with any conflicting radio frequency signals in the airspace comprises the step of transmitting a radio frequency signal in a non-interrogation manner.

14. A method for announcing the position of a first aircraft at a first position to a receiver located at a second position as defined in claim 1 wherein the step of transmitting the first radio frequency signal comprises the step of transmitting the first radio frequency signal in the frequency range from about and including the VHF band to about and including the SHF band.

15. A method for announcing the position of a first aircraft at a first position to a receiver located at a second position as defined in claim 1 wherein the step of transmitting the first radio frequency signal comprises the step of transmitting the first radio frequency signal in a substantially omnidirectional pattern.

16. A method for announcing the position of a first aircraft at a first position to a receiver located at a second position as defined in claim 1 further comprising the step of repeating steps (a) through (g).

17. A method for announcing the position of a first aircraft at a first position to a receiver located at a second position as defined in claim 16 wherein the step of monitoring the position of the first aircraft comprises the step of repeatedly displaying the position of the first aircraft on a display as the aircraft changes position.

18. A method for announcing the position of a first aircraft at a first position to a receiver located at a second position as defined in claim 17 wherein the step of monitoring the position of the first aircraft further comprises the step of displaying the heading and the speed of the first aircraft on a display.

19. A method for announcing the position of a first aircraft at a first position to a receiver located at a second position as defined in claim 1 wherein the step of monitoring the position of the first aircraft comprises the step of displaying the relative position of the first aircraft on a display over a selected period of time.

20. A method for announcing the position of a first aircraft at a first position to a receiver located at a second position as defined in claim 1 further comprising the step of determining the location of the second position relative to the fixed reference and wherein the step of monitoring the position of the first aircraft comprises the step of displaying the position of the first aircraft and the location of the second position.

21. A method of tracking the position of a first craft by monitoring receiver at a second craft, the first craft and the monitoring receiver being within a predetermined range of each other, the method comprising the steps of:

(a) determining, internally to the first craft using an external automated navigational system, the first craft'"'"'s position in at least one plane of space;

(b) encoding for the first craft an identification code, the presence or absence of any current communication radio frequency and the first craft'"'"'s position, all in a form which can be carried by a first radio frequency signal;

(c) determining when the first radio frequency signal should be transmitted;

(d) transmitting the first radio frequency signal;

(e) receiving the first radio frequency signal at the monitoring receiver of the second craft;

(f) decoding at the monitoring receiver of the second craft the first craft'"'"'s identification code, any current communication radio frequency and the position from the first radio frequency signal;

(g) displaying the identification code, any current communication radio frequency and the position of the first craft at the monitoring receiver of the second craft; and

(h) repeating steps (a) through (g).

22. A method of tracking the position of a first craft by a monitoring receiver, the first craft and the monitoring receiver being within a predetermined range of each other, as defined in claim 21 wherein the step of determining the first craft'"'"'s position comprises the step of determining the first craft'"'"'s position using a LORAN receiver.

23. A method of tracking the position of a first craft by a monitoring receiver, the first craft and the monitoring receiver being within a predetermined range of each other, as defined in claim 21 wherein the step of determining the first craft'"'"'s position comprises the step of determining the first craft'"'"'s position using a GPS receiver.

24. A method of tracking the position of a first craft by a monitoring receiver, the first craft and the monitoring receiver being within a predetermined range of each other, as defined in claim 21 wherein the first craft'"'"'s position is defined in reference to the latitude and longitude of the first craft.

25. A method of tracking the position of a first craft by a monitoring receiver, the first craft and the monitoring receiver being within a predetermined range of each other, as defined in claim 24 wherein the step of determining the first craft'"'"'s position further comprises the step of determining the altitude of the first craft.

26. A method of tracking the position of a first craft by a monitoring receiver, the first craft and the monitoring receiver being within a predetermined range of each other, as defined in claim 24 or 25 wherein the step of encoding the first craft'"'"'s position comprises the step of encoding the position of the first craft into a digital pulse train.

27. A method of tracking the position of a first craft by a monitoring receiver, the first craft and the monitoring receiver being within a predetermined range of each other, as defined in claim 26 wherein the step of encoding the position of the first craft'"'"'s position further comprises the step of translating the position of the first craft into an audio signal.

28. A method of tracking the position of a first craft by a monitoring receiver, the first craft and the monitoring receiver being within a predetermined range of each other, as defined in claim 21 further comprising the step of avoiding conflicts with any conflicting radio frequency signals in the airspace.

29. A method of tracking the position of a first craft by a monitoring receiver, the first craft and the monitoring receiver being within a predetermined range of each other, as defined in claim 28 wherein the step of avoiding conflicts with any conflicting radio frequency signals in the airspace comprises the step of listening for any conflicting radio frequency signals.

30. A method of tracking the position of a first craft by a monitoring receiver, the first craft and the monitoring receiver being within a predetermined range of each other, as defined in claim 28 wherein the step of avoiding conflicts with any conflicting radio frequency signals in the airspace comprises the step of waiting a period of time prior to transmission.

31. A method of tracking the position of a first craft by a monitoring receiver, the first craft and the monitoring receiver being within a predetermined range of each other, as defined in claim 28 wherein the step of avoiding conflicts with any conflicting radio frequency signals in the airspace comprises the step of waiting a predetermined period of time prior to transmission.

32. A method of tracking the position of a first craft by a monitoring receiver, the first craft and the monitoring receiver being within a predetermined range of each other, as defined in claim 21 or 28 wherein the step of avoiding conflicts with any conflicting radio frequency signals in the airspace comprises the step of transmitting a radio frequency signal in a non-interrogation manner.

33. A method of tracking the position of a first craft by a monitoring receiver, the first craft and the monitoring receiver being within a predetermined range of each other, as defined in claim 21 wherein the step of transmitting the first radio frequency signal comprises the step of transmitting the first radio frequency signal in the frequency range from about and including the VHF band to about and including the SHF band.

34. A method of tracking the position of a first craft by a monitoring receiver, the first craft and the monitoring receiver being within a predetermined range of each other, as defined in claim 21 wherein the step of transmitting the first radio frequency signal comprises the step of transmitting the first radio frequency signal in a substantially omnidirectional pattern.

35. A method of tracking the position of a first craft by a monitoring receiver, the first craft and the monitoring receiver being within a predetermined range of each other, as defined in claim 21 wherein the step of displaying the position of the first craft at the monitoring receiver comprises the step of repeatedly displaying the position of the first craft on a display of the second craft as the first craft changes position.

36. A method of tracking the position of a first craft by a monitoring receiver, the first craft and the monitoring receiver being within a predetermined range of each other, as defined in claim 21 wherein the step of displaying the position of the first craft at the monitoring receiver further comprises the step of displaying the heading and the speed of the first craft on a display at the second craft.

37. A method of tracking the position of a first craft by a monitoring receiver, the first craft and the monitoring receiver being within a predetermined range of each other, as defined in claim 35 comprises the step of displaying the position of the second craft on a display, the second craft having the monitoring receiver on board.

38. A method of tracking the position of a first craft by a monitoring receiver, the first craft and the monitoring receiver being within a predetermined range of each other, as defined in claim 37 further comprising the step of determining the location of the second position relative to the fixed reference and wherein the step of displaying the position of the first craft comprises the step of displaying the position of the first craft and the location of the monitoring receiver on the display.

39. A method of tracking the position of a first craft from on board a second craft, the first and second craft being within a predetermined range of each other, the method comprising the steps of:

(a) determining on board the first craft using an existing automated navigational system the first craft'"'"'s position in at least two perpendicular planes of space which are of interest to the second craft;

(b) encoding for the first craft its identification code and the presence or absence of a current operating communication radio frequency on which voice contact can be initiated to the first craft, and encoding the first craft'"'"'s position, all in a form which can be carried by a first radio frequency signal;

(c) determining whether the first radio frequency signal will conflict with any other radio frequency signals;

(d) transmitting the first radio frequency signal;

(e) receiving the first radio frequency signal at the second craft;

(f) decoding and displaying the first craft'"'"'s identification code, current operating communication radio frequency if any and the first craft'"'"'s position, all from the first radio frequency signal, such that the first craft can potentially be contacted by voice communication;

(g) apprising the operator of the second craft when the position of the first craft is within an advisory range; and

(h) repeating steps (a) through (g).

40. A method of tracking the position of a first craft from on board a second craft, the first and second craft being within a predetermined range of each other, as defined in claim 39 wherein the step (a) of determining the first craft'"'"'s position comprises the step of receiving a LORAN signal and determining the first craft'"'"'s position in latitude and longitude.

41. A method of tracking the position of a first craft from on board a second craft, the first and second craft being within a predetermined range of each other, as defined in claim 39 wherein the step (a) of determining the first craft'"'"'s position comprises the step of receiving a GPS signal.

42. A method of tracking the position of a first craft from on board a second craft, the first and second craft being within a predetermined range of each other, as defined in claim 39 wherein said existing automated navigational system is available both within and outside the predetermined range.

43. A method of tracking the position of a first craft from on board a second craft, the first and second craft being within a predetermined range of each other, as defined in claim 42 wherein the step (a) of determining the first craft'"'"'s position comprises the step of determining the first craft'"'"'s position in latitude and longitude.

44. A method of tracking the position of a first craft from on board a second craft, the first and second craft being within a predetermined range of each other, as defined in claim 42 wherein the step (a) of determining the first craft'"'"'s position further comprises the step of determining the altitude of the first craft.

45. A method for announcing the position of a first aircraft at a first position to a receiver located at a second position as defined in claim 43 or 44 wherein the step of avoiding conflicts with any conflicting radio frequency signals in the airspace comprises the step of transmitting a radio frequency signal in a non-interrogation manner.

46. A method of tracking the position of a first craft from on board a second craft, the first and second craft being within a predetermined range of each other, as defined in claim 43 or 44 wherein the step of encoding the first craft'"'"'s position comprises the step of encoding the position of the first craft into a digital pulse train.

47. A method of tracking the position of a first craft from on board a second craft, the first and second craft being within a predetermined range of each other, as defined in claim 46 wherein the step of encoding the position of the first aircraft further comprises the step of translating the first craft'"'"'s position into an audio signal.

48. A method of tracking the position of a first craft from on board a second craft, the first and second craft being within a predetermined range of each other, as defined in claim 46 wherein the step of determining whether the first radio frequency signal will conflict with any other radio frequency signals comprises the steps of:

listening for any conflicting radio frequency signals; and

waiting a period of time prior to transmission.

49. A method of tracking the position of a first craft from on board a second craft, the first and second craft being within a predetermined range of each other, as defined in claim 48 wherein the step of waiting a period of time comprises the step of waiting a randomly assigned period of time.

50. A method of tracking the position of a first craft from on board a second craft, the first and second craft being within a predetermined range of each other, as defined in claim 39 wherein the step of encoding the first craft'"'"'s position comprises the step of encoding an identification code for the first craft so that the identification code can be carried by the first radio frequency signal and wherein the step of transmitting the first radio frequency signal comprises the steps of:

transmitting the first radio frequency signal in the frequency range from about and including the VHF band to about and including the SHF band;

transmitting the first radio frequency signal in a substantially omnidirectional pattern; and

transmitting the identification code for the first craft.

51. A method of tracking the position of a first craft from on board a second craft, the first and second craft being within a predetermined range of each other, as defined in claim 39 wherein the step of apprising the operator comprises the step of repeatedly displaying the position of the first craft on a display as the first craft changes position.

52. A method of tracking the position of a first craft from on board a second craft, the first and second craft being within a predetermined range of each other, as defined in claim 51 wherein the step of apprising the operator of the second craft comprises the steps of:

displaying the relative position and direction of travel of the first craft on a display; and

displaying the position of the second craft on a display.

53. A method of avoiding collisions between a first craft having a first identification code and at least a second craft having a second identification code, the first and second crafts coming within a predetermined range of each other, the method comprising the steps of:

(a) determining, on board to the first craft and using an existing automated navigational system, the first craft'"'"'s position in at least one plane in space which is of interest to the second craft to avoid a collision with the first craft;

(b) encoding the first craft'"'"'s position, identification code and the presence or absence of any current operating communication radio frequency on which voice contact with the first craft can be established, all to be carried by a first radio frequency signal;

(c) listening for any radio frequency signals present on the same frequency allocation as the first radio frequency signal;

(d) transmitting the first radio frequency signal carrying the first craft'"'"'s position, identification code and the presence or absence of any current communication radio frequency on which voice contact with the first craft can be established;

(e) receiving the first radio frequency signal at the second craft;

(f) decoding from the first radio frequency the first craft'"'"'s position, identification code and current communication radio frequency, if any, on which voice contact with the first craft can be established;

(g) determining the second craft'"'"'s position, on board the second craft by using said existing automated navigational system, and in at least one dimension of space, which is of interest to the operator of the second craft, to avoid a collision with the first craft;

(h) displaying, on board the second craft, the position, identification code and current communication radio frequency, if any, on which voice contact to the first craft can be established, and displaying the location of the second craft so that the operator of the second craft is apprised of the location of the both the first craft and the second craft so as to avoid a collision therebetween; and

(i) repeating steps (a) through (h). 232

54. A method of avoiding collisions between a first craft having a first identification code and at least a second craft having a second identification code, the first and second craft coming within a predetermined range of each other, as defined in claim 53 wherein the step of determining the first craft'"'"'s position comprises the step of receiving a LORAN signal or a GPS signal.

55. A method of avoiding collisions between a first craft having a first identification code and at least a second craft having a second identification code, the first and second craft coming within a predetermined range of each other, as defined in claim 54 wherein the first craft comprises an aircraft and wherein the step of determining first craft'"'"'s position comprises the step of determining the latitude, longitude, and altitude of the first aircraft.

56. A method of avoiding collisions between a first craft having a first identification code and at least a second craft having a second identification code, the first and second craft coming within a predetermined range of each other, as defined in claim 53 wherein the step of encoding the first craft'"'"'s position comprises the stop of encoding the latitude and longitude of the first craft into a digital pulse train which can be carried by a frequency modulated first radio frequency signal.

57. A method of avoiding collisions between a first craft having a first identification code and at least a second craft having a second identification code, the first and second craft coming within a predetermined range of each other, as defined in claim 53 further comprises the step of waiting a period of time after a conflicting radio frequency signal is heard prior to transmission of the first radio frequency signal, the period of time being different for the first craft and the second craft, the transmission of the first radio frequency signal being initiated without interrogation from another radio frequency signal.

58. A method of avoiding collisions between a first craft having a first identification code and at least a second craft having a second identification code, the first and second craft coming within a predetermined range of each other, as defined in claim 53 wherein the step of transmitting the first radio frequency signal comprises the step of transmitting the first radio frequency signal in the frequency range from about and including the VHF band to about and including the SHF band in a substantially omnidirectional pattern.

59. A method of avoiding collisions between a first craft having a first identification code and at least a second craft having a second identification code, the first and second craft coming within a predetermined range of each other, as defined in claim 53 wherein the step of displaying the position of the first craft comprises the step of displaying the relative direction of travel of the first craft on a display.

60. An apparatus for announcing the position of a first aircraft at a first position within airspace containing a plurality of other aircraft, to a receiver located at a second position within a predetermined range of the first aircraft, the first aircraft being within operational range of an existing navigational system which can provide position information in at least two planes of interest, the apparatus comprising:

means for making an on board determination of the position of the first aircraft using the existing navigational system;

means for encoding the position of the first aircraft, and any identification code and the presence or absence of any current communication radio frequency on which voice contact to the first aircraft can be made, into information which can be carried by a first radio frequency signal;

means for detecting the presence of any conflicting radio frequency signal which would interfere with the first radio frequency signal and determining whether transmission of the first radio frequency should proceed;

means for transmitting the first radio frequency signal from the first aircraft such that the radio frequency signal can be received at the receiver, decoded, and such that the position, identification code and current communication radio frequency, if any, on which voice contact can be made to the first aircraft is displayed.

61. An apparatus for announcing the position of a first aircraft at a first position to a receiver located at a second position within a predetermined range of the first aircraft, the first aircraft being within operational range of an existing navigational system which can provide position information in at least two planes of interest, as defined in claim 60 wherein the means for making an on board determination of the position of the first aircraft comprises a LORAN receiver.

62. An apparatus for announcing the position of a first aircraft at a first position to a receiver located at a second position within a predetermined range of the first aircraft, the first aircraft being within operational range of an existing navigational system which can provide position information in at least two planes of interest, as defined in claim 60 wherein the means for making an on board determination of the position of the first aircraft comprises a GPS receiver.

63. An apparatus for announcing the position of a first aircraft at a first position to a receiver located at a second position within a predetermined range of the first aircraft, the first aircraft being within operational range of an existing navigational system which can provide position information in at least two planes of interest, as defined in claim 60 wherein the means for making an on board determination of the position of the first aircraft comprises means for determining the latitude and longitude of the first aircraft.

64. An apparatus for announcing the position of a first aircraft at a first position to a receiver located at a second position within a predetermined range of the first aircraft, the first aircraft being within operational range of an existing navigational system which can provide position information in at least two planes of interest, as defined in claim 63 wherein the means for making an on board determination of the position of the first aircraft further comprises means for determining the altitude of the aircraft.

65. An apparatus for announcing the position of a first aircraft at a first position to a receiver located at a second position within a predetermined range of the first aircraft, the first aircraft being within operational range of an existing navigational system which can provide position information in at least two planes of interest, as defined in claim 60 wherein the means for transmitting the first radio frequency signal comprises a radio frequency transmitter operating in a frequency range from about and including the VHF band to about and including the SHF band.

66. An apparatus for announcing the position of a first aircraft at a first position to a receiver located at a second position within a predetermined range of the first aircraft, the first aircraft being within operational range of an existing navigational system which can provide position information in at least two planes of interest, as defined in claim 65 wherein the means for transmitting the first radio frequency signal further comprises an omnidirectional antenna.

67. An apparatus for announcing the position of a first aircraft at a first position to a receiver located at a second position within a predetermined range of the first aircraft, the first aircraft being within operational range of an existing navigational system which can provide position information in at least two planes of interest, as defined in claim 60 wherein the means for detecting the presence of any conflicting radio frequency signal comprises a radio frequency receiver.

68. An apparatus for announcing the position of a first aircraft at a first position to a receiver located at a second position within a predetermined range of the first aircraft, the first aircraft being within operational range of an existing navigational system which can provide position information in at least two planes of interest, as defined in claim 60 wherein the means for encoding the position of the first aircraft is further for encoding an identification code into information which can be carried by the first radio frequency signal.

69. An apparatus for announcing the position of a first aircraft at a first position to a receiver located at a second position within a predetermined range of the first aircraft, the first aircraft being within operational range of an existing navigational system which can provide position information in at least two planes of interest, as defined in claim 60 further comprising:

means for receiving a second radio frequency signal carrying the position and identification code for a second aircraft, and the presence or absence of any current communication radio frequency on which voice contact to the second aircraft can be established;

means for decoding from the second radio frequency signal the second aircraft'"'"'s position, identification code, and the presence of absence of any current communication radio frequency on which voice contact to the second aircraft can be established; and

means for displaying, on board the first aircraft, the second aircraft'"'"'s position, identification code, and the presence or absence of any current communication radio frequency on which voice contact to the second aircraft can be established so that the operator of the first craft is apprised of the position of the second aircraft and is potentially able to make voice contact with the second aircraft.

70. An apparatus for tracking the position of a second craft from on board a first craft, the first and the second craft being within range of an existing navigational system and within a predetermined range of each other, the apparatus comprising:

means, on board the first craft, for receiving a determination of the position of the first craft using the existing navigational system, the position of the first craft being determined in at least two planes of interest to the operator of the second craft;

means for encoding the first craft'"'"'s position, and any identification code and the presence or absence of any current communication radio frequency on which voice contact to the first craft can be made, in a form which can be carried by a first radio frequency signal;

means for transmitting the first radio frequency signal;

means for receiving a second radio frequency signal carrying the second craft'"'"'s position an identification code for the second craft and the presence or absence of any current communication radio frequency on which the second craft can contacted by voice;

means for decoding the second craft'"'"'s position, identification code and current communication radio frequency, if any, from the second radio frequency signal;

means for displaying, on board the first craft, the second craft'"'"'s position, identification code and current communication radio frequency, if any, decoded from the second radio frequency signal so that the operator of the first craft is apprised of the position, identification code and current communication radio frequency, if any, of the second craft.

71. An apparatus for tracking the position of a second craft from on board a first craft as defined in claim 70 wherein the means for receiving an on board determination of the position of the first craft comprises a data port adapted to receive data from a LORAN receiver.

72. An apparatus for tracking the position of a second craft from on board a first craft as defined in claim 70 wherein the means for receiving an on board determination of the position of the first craft comprises a data port adapted to receive data from a GPS receiver.

73. An apparatus for tracking the position of a second craft from on board a first craft as defined in claim 70 wherein the means for transmitting the first radio frequency signal comprises:

a radio frequency transmitter operating in a frequency range from about and including the VHF band to about and including the SHF band; and

an omnidirectional antenna system.

74. An apparatus for tracking the position of a second craft from on board a first craft as defined in claim 73 further comprising means for detecting the presence of any conflicting radio frequency signal.

75. An apparatus for avoiding collisions between a first craft having a first identification code and at least a second craft having a second identification code, the first craft being within range of an existing navigational system and the first and the second craft being within a predetermined range of each other, the apparatus comprising:

means for determining, on board the first craft and using the existing navigational system, the first craft'"'"'s position in at least one plane in space which is of interest to the second craft to avoid a collision with the first craft;

means for encoding the first craft'"'"'s position, the first identification code and the presence or absence of any current communication radio frequency on which the first craft can be contacted by voice, such that the encoded information is carried by a first radio frequency signal;

means for detecting the presence of any conflicting radio frequency signal and determining whether transmission of the first radio frequency should proceed;

means for transmitting the first radio signal;

means for receiving, on board the first craft, a second radio frequency signal transmitted from the second craft, the second radio frequency signal carrying the position of the second craft, the second identification code and the presence or absence of any current communication radio frequency on which the second craft can be contacted by voice;

means for decoding, on board the first craft, the second craft'"'"'s position, the second identification code and the presence or absence of any current communication radio frequency on which the second craft can be contacted by voice;

means for simultaneously displaying the first craft'"'"'s position and the second craft'"'"'s position on board the first craft so that the operator of the first craft is apprised of the position of the second craft, the second identification code and the presence or absence of any current communication radio frequency on which the second craft can be contacted by voice so as to avoid a collision therebetween.

76. An apparatus for avoiding collisions between a first craft having a first identification code and at least a second craft having a second identification code as defined in claim 75 wherein the means for determining the first craft'"'"'s position comprises a LORAN receiver.

77. An apparatus for avoiding collisions between a first craft having a first identification code and at least a second craft having a second identification code as defined in claim 75 wherein the means for determining the first craft'"'"'s position comprises a GPS receiver.

78. An apparatus for avoiding collisions between a first craft having a first identification code and at least a second craft having a second identification code as defined in claim 76 or 77 wherein the means for transmitting the first radio frequency signal comprises:

a radio frequency transmitter operating in a frequency range from about and including the VHF band to about and including the SHF band; and

an omnidirectional antenna system.

79. An apparatus for avoiding collisions between a first craft having a first identification code and at least a second craft having a second identification code as defined in claim 78 wherein the means for detecting the presence of any conflicting radio frequency signal comprises a radio frequency receiver.